1 //===- CoroCleanup.cpp - Coroutine Cleanup Pass ---------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "llvm/Transforms/Coroutines/CoroCleanup.h"
10 #include "CoroInternal.h"
11 #include "llvm/IR/IRBuilder.h"
12 #include "llvm/IR/InstIterator.h"
13 #include "llvm/IR/PassManager.h"
14 #include "llvm/IR/Function.h"
15 #include "llvm/Transforms/Scalar/SimplifyCFG.h"
16
17 using namespace llvm;
18
19 #define DEBUG_TYPE "coro-cleanup"
20
21 namespace {
22 // Created on demand if CoroCleanup pass has work to do.
23 struct Lowerer : coro::LowererBase {
24 IRBuilder<> Builder;
Lowerer__anond33a9e590111::Lowerer25 Lowerer(Module &M) : LowererBase(M), Builder(Context) {}
26 bool lower(Function &F);
27 };
28 }
29
lowerSubFn(IRBuilder<> & Builder,CoroSubFnInst * SubFn)30 static void lowerSubFn(IRBuilder<> &Builder, CoroSubFnInst *SubFn) {
31 Builder.SetInsertPoint(SubFn);
32 Value *FramePtr = SubFn->getFrame();
33 int Index = SubFn->getIndex();
34
35 auto *FrameTy = StructType::get(SubFn->getContext(),
36 {Builder.getPtrTy(), Builder.getPtrTy()});
37
38 Builder.SetInsertPoint(SubFn);
39 auto *Gep = Builder.CreateConstInBoundsGEP2_32(FrameTy, FramePtr, 0, Index);
40 auto *Load = Builder.CreateLoad(FrameTy->getElementType(Index), Gep);
41
42 SubFn->replaceAllUsesWith(Load);
43 }
44
lower(Function & F)45 bool Lowerer::lower(Function &F) {
46 bool IsPrivateAndUnprocessed = F.isPresplitCoroutine() && F.hasLocalLinkage();
47 bool Changed = false;
48
49 for (Instruction &I : llvm::make_early_inc_range(instructions(F))) {
50 if (auto *II = dyn_cast<IntrinsicInst>(&I)) {
51 switch (II->getIntrinsicID()) {
52 default:
53 continue;
54 case Intrinsic::coro_begin:
55 II->replaceAllUsesWith(II->getArgOperand(1));
56 break;
57 case Intrinsic::coro_free:
58 II->replaceAllUsesWith(II->getArgOperand(1));
59 break;
60 case Intrinsic::coro_alloc:
61 II->replaceAllUsesWith(ConstantInt::getTrue(Context));
62 break;
63 case Intrinsic::coro_async_resume:
64 II->replaceAllUsesWith(
65 ConstantPointerNull::get(cast<PointerType>(I.getType())));
66 break;
67 case Intrinsic::coro_id:
68 case Intrinsic::coro_id_retcon:
69 case Intrinsic::coro_id_retcon_once:
70 case Intrinsic::coro_id_async:
71 II->replaceAllUsesWith(ConstantTokenNone::get(Context));
72 break;
73 case Intrinsic::coro_subfn_addr:
74 lowerSubFn(Builder, cast<CoroSubFnInst>(II));
75 break;
76 case Intrinsic::coro_end:
77 case Intrinsic::coro_suspend_retcon:
78 if (IsPrivateAndUnprocessed) {
79 II->replaceAllUsesWith(UndefValue::get(II->getType()));
80 } else
81 continue;
82 break;
83 case Intrinsic::coro_async_size_replace:
84 auto *Target = cast<ConstantStruct>(
85 cast<GlobalVariable>(II->getArgOperand(0)->stripPointerCasts())
86 ->getInitializer());
87 auto *Source = cast<ConstantStruct>(
88 cast<GlobalVariable>(II->getArgOperand(1)->stripPointerCasts())
89 ->getInitializer());
90 auto *TargetSize = Target->getOperand(1);
91 auto *SourceSize = Source->getOperand(1);
92 if (TargetSize->isElementWiseEqual(SourceSize)) {
93 break;
94 }
95 auto *TargetRelativeFunOffset = Target->getOperand(0);
96 auto *NewFuncPtrStruct = ConstantStruct::get(
97 Target->getType(), TargetRelativeFunOffset, SourceSize);
98 Target->replaceAllUsesWith(NewFuncPtrStruct);
99 break;
100 }
101 II->eraseFromParent();
102 Changed = true;
103 }
104 }
105
106 return Changed;
107 }
108
declaresCoroCleanupIntrinsics(const Module & M)109 static bool declaresCoroCleanupIntrinsics(const Module &M) {
110 return coro::declaresIntrinsics(
111 M, {"llvm.coro.alloc", "llvm.coro.begin", "llvm.coro.subfn.addr",
112 "llvm.coro.free", "llvm.coro.id", "llvm.coro.id.retcon",
113 "llvm.coro.id.async", "llvm.coro.id.retcon.once",
114 "llvm.coro.async.size.replace", "llvm.coro.async.resume"});
115 }
116
run(Module & M,ModuleAnalysisManager & MAM)117 PreservedAnalyses CoroCleanupPass::run(Module &M,
118 ModuleAnalysisManager &MAM) {
119 if (!declaresCoroCleanupIntrinsics(M))
120 return PreservedAnalyses::all();
121
122 FunctionAnalysisManager &FAM =
123 MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
124
125 FunctionPassManager FPM;
126 FPM.addPass(SimplifyCFGPass());
127
128 PreservedAnalyses FuncPA;
129 FuncPA.preserveSet<CFGAnalyses>();
130
131 Lowerer L(M);
132 for (auto &F : M) {
133 if (L.lower(F)) {
134 FAM.invalidate(F, FuncPA);
135 FPM.run(F, FAM);
136 }
137 }
138
139 return PreservedAnalyses::none();
140 }
141